Conclusion
This study showed that the overall m6 A modification level and mRNA expression levels of m6 A-associated factors were not affected after acute and chronic morphine exposure in different brain regions, indicating m6 A modification may not be involved in brain response to morphine exposure.
Methods
In this study, we conducted a direct comparison of m6 A levels and mRNA expression of m6 A-associated factors between morphine-treated and nontreated C57BL/6 wild-type mice. We established animal models of both acute and chronic morphine treatment and confirmed the rewarding effects of chronic morphine treatment using the conditioned place preference (CPP) assay. The activation status of different brain regions in response to morphine was assessed by c-fos staining. To assess overall m6 A modification levels, we employed the m6 A dot blot assay, while mRNA levels of m6 A-associated proteins were measured using a quantitative polymerase chain reaction (qPCR) assay. These analyses were performed to investigate whether and how m6 A modification and m6 A-associated protein expression will change following morphine exposure.
Results
The overall m6 A methylation and mRNA levels of m6 A-associated proteins were not significantly altered in brain regions that were either activated or not activated during acute morphine stimulation. Similarly, the overall m6 A modification and mRNA levels of m6 A-associated proteins remained unaffected in several key brain regions associated with reward following chronic morphine exposure.